“The warmists still insist the planet is warming, and they want us to attempt to cool it down. Meanwhile the freezing temperatures have killed an extra 2000 pensioners.

When will the f*ckwits who think climate change making the earth cooler is a good thing start to apologise. History has shown us that civilisation flourishes in warm and ebbs away in the cold. Yet they insist on pushing us down the path of cooling the planet.”

Of course this is just cherry picking on a grand scale. Climate change deniers like Slater (and his mates at the local contrarian/denier blog Climate Conversation Group) seem to spend the New Zealand summer and autumn in the northern hemisphere, intellectually anyway. They continually comment on, and lament, snow storms and freezing pensioners in the UK, Canada or the US, while the rest of us are moaning about the local record droughts and high temperatures.

And they blatantly imagine their comments on regional weather are somehow directly relevant to global trends. Well, they aren’t – and there is plenty of data showing that. Here are recent examples from Arctic News (see Huge patches of warm air over the Arctic).

Have a look at the colour codes. Sure the UK is suffering from lower than normal temperatures (blue/purple) – but other regions suffer from higher than normal temperature (yellow/red).

Naturally Arctic News is concerned about the Arctic. The blog comments:

“Over the past month or so, huge patches with temperature anomalies of over 20 degrees Celsius have been forming over the Arctic.

The three images [above] show such patches stretch out from Svalbard to Novaya Zemlya (top), north of Eastern Siberia (middle) and over West Greenland and Baffin Bay (bottom).”

The comment further:

“Indeed, as the jet stream slows down and becomes more wavier, such patches of warm air can be expected to extend more regularly into the Arctic. The result can be a huge melt of Arctic sea ice, as well as a huge melt of snow cover in Greenland, which also dramatically lowers albedo, as occurred in 2012 and as discussed in the earlier post Greenland is melting at incredible rate.

This spells bad news for the Arctic sea ice, which may well disappear altogether this summer.”

Cameron Slater and his mates are very parochial – but during our summer/autumn months they seem to be living in a completely different hemisphere. (Some commentators suspect they actually live in a different world).

“Forty-seven glaciologists have arrived at a community consensus over all the data on what the past century’s warming has done to the great ice sheets: a current annual loss of 344 billion tons of glacial ice, accounting for 20% of current sea level rise. Greenland’s share—about 263 billion tons—is roughly what most researchers expected, but Antarctica’s represents the first agreement on a rate that had ranged from a far larger loss to an actual gain. The new analysis, published on page 1183 of this week’s issue of Science, also makes it clear that losses from Greenland and West Antarctica have been accelerating, showing that some ice sheets are disconcertingly sensitive to warming.”

Over recent years climate change deniers/contrarians/sceptics have cherry picked data to counter any suggestion that the earth’s large ice sheets are melting. They have pointed to increased amounts of ice in Eastern Antarctica to balance reports of massive losses of ice in the Arctic. (Have a look at this animation to see how such data can be cherry picked). Similarly they have tried to hide concern of the loss of land ice by stressing reports of local increases in sea ice.

But the paper by Shepperd et al. combined data from satellite altimetry, interferometry, and gravimetry measurements. This provides more reliable estimates of changes in the ice sheets, and gives some detail of these changes. This figure from the paper gives an idea of the detail of their findings. It shows that all the major regions of the polar ice sheets except one (East Antarctica) have lost mass since 1992. The authors also estimate that mass loss from the polar ice sheets has contributed roughly 20 percent of the total global sea level rise during that period (at a rate of 0.59 ± 0.20 millimeter year−1 ).

It’s amazing the confusion that accompanies climate change questions. That’s partly because it is a complex subject. So it’s not surprising that people can make glaring mistakes.

Here’s one, though, that’s easy to get your head around by a simple experiment you can do at home. It relates to the question of melting of the ice sheets in Greenland and Antarctica. David Attenborough covered this in the last episode of “The Frozen Planet” screened here recently. His point – that global warming could cause loss of this land ice into the sea leading to dramatic increases in sea level.

Of course, this gets denied by the climate change deniers. I came across one recently who suggested an experiment to prove Attenborough wrong:

” I can only suggest that every one do the following experiment. Take one half glass of water. Add two or three ice cubes. On the outside of the glass mark the level of the water. Leave for a few hours until the ice has melted entirely. Note the water level compared with the mark.”

Well, yes. Think about it – look at the image. Melting those ice cubes is not going to make much difference to the water level is it? Most of their volume is already under water and there already contributing to the water level.

This is why melting of floating icebergs due to global warming will have a relatively small effect.

But that’s not what Attenborough was talking about.

His comments related to movement of ice from the ice sheets on Greenland and Antarctica into the sea. Partly from melting. But also from sliding of the ice sheet in Greenland as the water melt lubricates the ice/rock junction. And in Antarctica the fear is that warmer sea temperatures will diminish the effect of pack ice restraining glacier ice from moving into the sea. In both cases the problem arises from addition of land ice to the sea.

So here’s the proper experiment:

Take one half glass of water. On the outside of the glass mark the level of the water. Now add your three ice cubes. Leave for a few hours until the ice has melted entirely. Note the water level compared with the mark.”

Or even quicker.

Note the water level immediately after addition of the ice cubes!

Think about it! Try it at home.

Footnote: Much of the research on mechanisms of movement of these land ice sheets into the sea is relatively new. many of the current findings were jsut not available during preparation of the 1987 IPCC Fourth Assessment Report. Consequently the concern is that the effects of climate warming may be greater than estimated by that review.